Frontlines, Intersections, and Creativity: The Growth of the North American Climate Justice Movement

This is the first part of a three-part paper on North American climate in phase 5 of the Coupled Model Intercomparison Project (CMIP5) that evaluates the historical simulations of continental and regional climatology with a focus on a core set of 17 models. The authors evaluate the models for a set of basic surface climate and hydrological variables and their extremes for the continent. This is supplemented by evaluations for selected regional climate processes relevant to North American climate, including cool season western Atlantic cyclones, the North American monsoon, the U.S. Great Plains low-level jet, and Arctic sea ice. In general, the multimodel ensemble mean represents the observed spatial patterns of basic climate and hydrological variables but with large variability across models and regions in the magnitude and sign of errors. No single model stands out as being particularly better or worse across all analyses, although some models consistently outperform the others for certain variables across most regions and seasons and higher-resolution models tend to perform better for regional processes. The CMIP5 multimodel ensemble shows a slight improvement relative to CMIP3 models in representing basic climate variables, in terms of the mean and spread, although performance has decreased for some models. Improvements in CMIP5 model performance are noticeable for some regional climate processes analyzed, such as the timing of the North American monsoon. The results of this paper have implications for the robustness of future projections of climate and its associated impacts, which are examined in the third part of the paper.

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On North American Decadal Climate for 2011–20

Journal of Climate ◽

10.1175/2011jcli4137.1 ◽

2011 ◽

Vol 24 (16) ◽

pp. 4519-4528 ◽

Cited By ~ 29

Author(s):

Martin Hoerling ◽

James Hurrell ◽

Arun Kumar ◽

Laurent Terray ◽

Jon Eischeid ◽

...

Keyword(s):

North American ◽

Climate Models ◽

Noise Analysis ◽

Surface Air Temperature ◽

Internal Variability ◽

External Signal ◽

Initial State ◽

The North ◽

Decadal Scale ◽

North American Climate

Abstract The predictability of North American climate is diagnosed by taking into account both forced climate change and natural decadal-scale climate variability over the next decade. In particular, the “signal” in North American surface air temperature and precipitation over 2011–20 associated with the expected change in boundary conditions related to future anthropogenic greenhouse gas (GHG) forcing, as well as the “noise” around that signal due to internally generated ocean–atmosphere variability, is estimated. The structural uncertainty in the estimate of decadal predictability is diagnosed by examining the sensitivity to plausible scenarios for the GHG-induced change in boundary forcing, the model dependency of the forced signals, and the dependency on methods for estimating internal decadal noise. The signal-to-noise analysis by the authors is thus different from other published decadal prediction studies, in that this study does not follow a trajectory from a particular initial state but rather considers the statistics of internal variability in comparison with the GHG signal. The 2011–20 decadal signal is characterized by surface warming over the entire North American continent, precipitation decreases over the contiguous United States, and precipitation increases over Canada relative to 1971–2000 climatological conditions. The signs of these forced responses are robust across different sea surface temperature (SST) scenarios and the different models employed, though the amplitude of the response differs. The North American decadal noise is considerably smaller than the signal associated with boundary forcing, implying a potential for high forecast skill for 2011–20 North American climate even for prediction methods that do not attempt to initialize climate models. However, the results do suggest that initialized decadal predictions, which seek to forecast externally forced signals and also constrain the internal variability, could potentially improve upon uninitialized methods in regions where the external signal is small relative to internal variability.

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Impacts of the Atlantic Multidecadal Variability on North American Summer Climate and Heat Waves

Journal of Climate ◽

10.1175/jcli-d-17-0270.1 ◽

2018 ◽

Vol 31 (9) ◽

pp. 3679-3700 ◽

Cited By ~ 15

Author(s):

Yohan Ruprich-Robert ◽

Thomas Delworth ◽

Rym Msadek ◽

Frederic Castruccio ◽

Stephen Yeager ◽

...

Keyword(s):

United States ◽

North Atlantic ◽

North American ◽

Heat Waves ◽

Southern United States ◽

Atlantic Multidecadal Variability ◽

Multidecadal Variability ◽

Northern Mexico ◽

The North ◽

North American Climate

The impacts of the Atlantic multidecadal variability (AMV) on summertime North American climate are investigated using three coupled global climate models (CGCMs) in which North Atlantic sea surface temperatures (SSTs) are restored to observed AMV anomalies. Large ensemble simulations are performed to estimate how AMV can modulate the occurrence of extreme weather such as heat waves. It is shown that, in response to an AMV warming, all models simulate a precipitation deficit and a warming over northern Mexico and the southern United States that lead to an increased number of heat wave days by about 30% compared to an AMV cooling. The physical mechanisms associated with these impacts are discussed. The positive tropical Atlantic SST anomalies associated with the warm AMV drive a Matsuno–Gill-like atmospheric response that favors subsidence over northern Mexico and the southern United States. This leads to a warming of the whole tropospheric column, and to a decrease in relative humidity, cloud cover, and precipitation. Soil moisture response to AMV also plays a role in the modulation of heat wave occurrence. An AMV warming favors dry soil conditions over northern Mexico and the southern United States by driving a year-round precipitation deficit through atmospheric teleconnections coming both directly from the North Atlantic SST forcing and indirectly from the Pacific. The indirect AMV teleconnections highlight the importance of using CGCMs to fully assess the AMV impacts on North America. Given the potential predictability of the AMV, the teleconnections discussed here suggest a source of predictability for the North American climate variability and in particular for the occurrence of heat waves at multiyear time scales.

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NAC 2 H: The North American Climate Change and Hydroclimatology Data Set

Water Resources Research ◽

10.1029/2020wr027097 ◽

2020 ◽

Vol 56 (8) ◽

Author(s):

Richard Arsenault ◽

François Brissette ◽

Jie Chen ◽

Qiang Guo ◽

Gabrielle Dallaire

Keyword(s):

Climate Change ◽

North American ◽

Data Set ◽

The North ◽

North American Climate

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A review on energy, economical, and environmental benefits of the use of CHP systems for small commercial buildings for the North American climate

International Journal of Energy Research ◽

10.1002/er.1630 ◽

2009 ◽

Vol 33 (14) ◽

pp. 1252-1265 ◽

Cited By ~ 47

Author(s):

P. J. Mago ◽

L. M. Chamra ◽

A. Hueffed

Keyword(s):

North American ◽

Commercial Buildings ◽

Environmental Benefits ◽

The North ◽

North American Climate

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Quasi-biweekly oscillation over the western North Pacific in boreal winter and its influence on the central North American air temperature

Journal of Climate ◽

10.1175/jcli-d-21-0531.1 ◽

2021 ◽

pp. 1-43

Keyword(s):

North America ◽

North American ◽

North Pacific ◽

Western North Pacific ◽

Wave Train ◽

The Philippines ◽

Climate Impacts ◽

Boreal Winter ◽

The North ◽

North American Climate

Abstract This study investigates the characteristics and climate impacts of the quasi-biweekly oscillation (QBWO) over the western North Pacific (WNP) in boreal winter based on observational and reanalysis data and numerical experiments with a simplified model. The wintertime convection over the WNP is dominated by significant biweekly variability with a 10–20-day period, which explains about 66% of the intraseasonal variability. Its leading mode on the biweekly timescale is a northwestward-propagating convection dipole over the WNP, which oscillates over a period of about 12 days. When the convection-active center of this QBWO is located to the east of the Philippines, it can generate an anticyclonic vorticity source to the south of Japan via inducing upper-tropospheric divergence and excite a Rossby wave train propagating towards North America along the Pacific rim. The resultant lower-tropospheric circulation facilitates cold advection and leads to cold anomalies over central North America in the following week. This result highlights a cause-effect relationship between the WNP convection and the North American climate on the quasi-biweekly timescale and may provide some prediction potential for the North American climate.

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Interactions between the Responses of North American Climate to El Niño–La Niña and to the Secular Warming Trend in the Indian–Western Pacific Oceans

Journal of Climate ◽

10.1175/2007jcli1899.1 ◽

2008 ◽

Vol 21 (3) ◽

pp. 476-494 ◽

Cited By ~ 27

Author(s):

Ngar-Cheung Lau ◽

Ants Leetmaa ◽

Mary Jo Nath

Keyword(s):

North American ◽

El Niño ◽

General Circulation ◽

El Nino ◽

Warming Trend ◽

La Niña ◽

Western Pacific ◽

The North ◽

La Nina ◽

North American Climate

Abstract The modulation of El Niño and La Niña responses by the long-term sea surface temperature (SST) warming trend in the Indian–Western Pacific (IWP) Oceans has been investigated using a large suite of sensitivity integrations with an atmospheric general circulation model. These model runs entail the prescription of anomalous SST conditions corresponding to composite El Niño or La Niña episodes, to SST increases associated with secular warming in IWP, and to combinations of IWP warming and El Niño/La Niña. These SST forcings are derived from the output of coupled model experiments for climate settings of the 1951–2000 and 2001–50 epochs. Emphasis is placed on the wintertime responses in 200-mb height and various indicators of surface climate in the North American sector. The model responses to El Niño and La Niña forcings are in agreement with the observed interannual anomalies associated with warm and cold episodes. The wintertime model responses in North America to IWP warming bear a distinct positive (negative) spatial correlation with the corresponding responses to La Niña (El Niño). Hence, the amplitude of the combined responses to IWP warming and La Niña is notably higher than that to IWP warming and El Niño. The model projections indicate that, as the SST continues to rise in the IWP sector during the twenty-first century, the strength of various meteorological anomalies accompanying La Niña (El Niño) will increase (decrease) with time. The response of the North American climate and the zonal mean circulation to the combined effects of IWP forcing and La Niña (El Niño) is approximately equal to the linear sum of the separate effects of IWP warming and La Niña (El Niño). The summertime responses to IWP warming bear some similarity to the meteorological anomalies accompanying extended droughts and heat waves over the continental United States.

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